1. Field of the Invention
The present invention relates to a stereo camera diagnosing device and a stereo camera diagnostic method, which are used at the time of diagnosing a stereo camera which measures the distance between each point within an image, and the projected center thereof, the image having been taken from multiple viewpoints having a predetermined positional relation, by the principle of triangulation. The present invention particularly relates to a stereo camera diagnosing device which assists diagnostic work for a stereo camera mounted on a robot, and a method for diagnosing a stereo camera mounted on a robot apparatus.
In further detail, the present invention relates to a stereo camera diagnosing device which assists diagnosing of positional offset of a stereo camera due to deterioration of the stereo camera over time, falling of the robot apparatus on which the camera is mounted, and to a method for diagnosing a stereo camera mounted on a robot apparatus, and in particular relates to a stereo camera diagnosing device which is used at the time of diagnosing a stereo camera using the automatic diagnostic function of an intelligent robot apparatus, and a method for diagnosing a stereo camera mounted on a robot apparatus.
2. Description of the Related Art
An apparatus for performing operations similar to human movement using electric or magnetic action is referred to as a “robot”. It is said that the origin of the term “robot” is derived from the word “ROBOTA”, which means a slave machine in Slavic. Recently, study and development regarding various types of ambulatory mobile robots including “human-type” or “humanoid” robots designed after the body mechanism or actions of the animals like human beings who perform bipedal ambulation in erect posture is progressing, and demand for practical application of robots is increasing.
Most working spaces and living spaces for human beings are formed so as to match the behavioral patterns of bipedal ambulation in the erect posture possessed by human beings. In other words, in the living spaces of human beings, there are many obstacles for current mechanical systems using wheels as transporting means to move. In order for robots to assist or stand in for human tasks, and further become commonplace in human living spaces, the mobile range of the robots will need to become almost the same as that of human beings. This is the reason why there are great expectations for practical implementation of ambulatory mobile robots.
Such a humanoid robot can be applied to various types of work in industrial activities and production activities on behalf of human beings. For example, human beings have humanoid robots engaged on behalf of themselves in dangerous and hard work at sites such as maintenance work in an atomic power plants, thermal power plants, and petrochemical plants, transport and assembly of parts in manufacturing facilities, cleaning in high-rise buildings, and rescue at fire sites or the like where humans cannot readily go.
Also, examples of other usage of humanoid robots include so-called “harmonious coexistence” or “entertainment”, in which the robot shares a living space with human beings. With this type of usage, the robot is placed in the same work environment as human beings, such as in a family environment, and used in this environment. This case takes on the character of “living together” rather than performing tasks instead of humans.
Intelligent mobile robots perform autonomous thinking control and action control, and also execute autonomous actions in accordance with a time series model for generating actions. Moreover, the robots can expand autonomous actions and the working range, and realize realistic communication with human beings at a more intelligent level by being equipped with an image input device and audio input/output device, and performing environment recognition with image processing and audio processing (see Japanese Unexamined Patent Application Publication No. 2002-283261, for example).
For example, equipping a mobile robot with functions such as image input, image processing, and image recognition allows the robot to detect landmarks disposed at various places within a working environment so as to execute predetermined actions, thereby guiding the robot even in an state where no humans are present (see Japanese Unexamined Patent Application Publication No. 2002-149240 and Japanese Unexamined Patent Application Publication No. 2003-166824, for example).
Furthermore, mounting a stereo camera serving as an image input device on the robot allows the robot to precisely recognize the distance up to obstacles scattered through a working space, so as to avoid these obstacles, and to identify a floor face so as to recognize irregularities thereof, which can be utilized for correction of walking routes and control of attitude stability. A stereo camera is made up of multiple cameras (most commonly two cameras) each having different viewpoints (projected center) which are maintained at a predetermined positional relation, and measures the distance between each point within an image taken from multiple viewpoints and the projected center using the principle of triangulation.
Now, a bipedal ambulatory mobile robot comprises many link systems, including redundant degree-of-freedoms, whereby the robot can perform complex actions, and also simultaneously execute multiple tasks such as movement, maintenance of balance, and arm work. On the other hand, the robot has difficulty in maintaining attitude stability of itself, whereby it is assumed that the robot may fall down during walking or performing other tasks using the legs thereof.
For example, in the event that a stereo camera is mounted on the head of a robot, there is a problem wherein changing the relative position of the camera cannot correctly perform stereo distance measurement, even though the camera is not damaged. Furthermore, there is the possibility that deterioration over time may cause the relative position of the camera to change, even if falling or other impact is not applied to the camera.
Performing recalibration can recover the performance of a stereo camera, but requires special tools, and cannot be readily performed due to issues of the number of steps involved in recalibration, and the amount of time and technology involved.
Also, a method for easily performing calibration again using suitable corresponding points within images acquired by the left and right cameras and the like have been proposed, but there is a problem in terms of calibration accuracy.